This invention relates to a radiotelephone instrument adapted to be worn on the wrist of a user.
Recent progress in microelectronics has greatly miniaturized radio communication devices such as receivers, transmitters and antennas. This miniaturization has permitted the integration of these components into wrist-carried radiotelephone instruments.
Such a portable wrist-carried radiotelephone instrument is disclosed, for example, in U.S. Pat. No. 5,239,521, issued Aug. 24, 1993, to Blonder. The disclosed wrist-carried radiotelephone instrument comprises a case having a display and a strap having a top layer and a bottom layer. The top layer of the strap has a releasable end to allow the top layer to separate from the bottom layer in the area where one end of the strap is attached to the case. The top layer of the strap remains attached to the bottom layer of the strap via a hinge which also permits the top layer to rotate. The hinged area of the strap is located on the inner wrist of the wearer. Embedded within the top layer of the strap are a microphone and a speaker which are connected via conductors to a transceiver disposed within the case. The speaker is located at the releasable end of the top layer of the strap and the microphone is located at the hinged end of the top layer of the strap.
In operation, the top layer of the strap is released from the bottom layer and is rotated in such a way that the speaker is located in the palm of the user's hand and the microphone is located along the inside of the user's wrist. The user's hand is then raised so that the user's palm is cupped over the user's ear. Sound ports are located on the front side of the speaker facing the user's ear. The user's hand is oriented such that the user's palm containing the speaker is proximate the user's ear and the microphone is proximate the user's mouth. This arrangement allows the instrument to be used as a telephone.
While effective for its intended purpose, it has been found that the aforedescribed instrument is limited in that the distance between the speaker and the microphone is fixed and may not be suitable for all users, especially those not of average size. It is therefore a primary object of the present invention to provide a wrist-carried radio telephone instrument of the type described wherein the speaker-to-microphone distance is automatically adjustable to fit every user.